A union representing technical staff at Aer Lingus said it expected the Irish airline to cut or relocate 55 employees from Ireland's Shannon Airport, a move it says is likely to lead to industrial action.
The Unite trade union said it believed the airline was planning to announce the closure of its maintenance operations in Shannon within weeks.
"If they announce the sale of the hangar at the end of June, I would think industrial action will start immediately," union official Brian Gormley told Reuters.
A spokesman for Aer Lingus said the airline was in consultations with staff and their representatives in relation to potential relocation of some Shannon maintenance operations, but declined further comment.
Workers are to meet with union officials on Tuesday to decide on what action might be taken, Unite said in a statement.
"I don't know for definite what members will call for, but I couldn't see much point in anything less than a withdrawal of labor," Gormley said.
Any action is likely involve less than 10 percent of the airline's workforce but cause significant disruption to the airline during the summer season, Gormley said.
Aer Lingus flights were halted for three weeks in January last year in an industrial dispute with cabin crew. In February the airline said it was in talks with staff over a shortfall in a pension scheme in order to avoid industrial action.